This is potentially a major problem, and it's not something you should ignore. Here's why:
* Low Fluid Pressure: The most likely culprit is low hydraulic pressure within the transmission. This could be due to a failing transmission pump, worn internal seals, or a significant internal leak. Reving the engine temporarily increases pressure, allowing the transmission to engage.
* Valve Body Issues: A problem with the transmission valve body (which controls fluid flow) could also be responsible. A sticking or failing valve could be preventing proper pressure build-up in the drive circuit.
* Torque Converter Issues: While less likely, a problem with the torque converter could contribute.
Ignoring the problem is risky. Driving with intermittent transmission engagement is dangerous and could lead to further damage, potentially requiring a very expensive transmission rebuild or replacement.
Next Steps:
1. Check the Transmission Fluid Level: Make absolutely sure the transmission fluid level is correct and that the fluid is clean and red (not brown or burnt). An incorrect level can easily cause low pressure.
2. Professional Inspection: Take your Lumina to a qualified transmission specialist or mechanic. They have the tools and expertise to properly diagnose the problem. A simple visual inspection and fluid analysis is unlikely to pinpoint the problem. They likely need to test fluid pressure directly at various points in the system.
3. Avoid Driving Extensively: Limit your driving until the problem is diagnosed and repaired to prevent further damage.
In short, while it's *possible* a minor fix might solve the issue, the symptoms strongly suggest a more serious internal transmission problem requiring professional attention. Don't delay seeking professional help.
